This invention relates to computed tomographic (CT) imaging, and more particularly to methods and apparatus for the detection and diagnosis of abnormalities related to two forms of heart disease, namely, ischemic heart disease and abnormalities in the structure of the heart""s muscle and valves.
In spite of recent advancements in CT technology (faster scanning speed, larger coverage with multiple detector rows), energy resolution is still a missing piece, namely, wide x-ray photon energy spectrum from the x-ray source and the lack of energy resolution from CT detection systems. X-ray attenuation through a given object is not a constant. It is strongly dependent on the x-ray photon energy. This physical phenomenon shows in the image as a beam-hardening artifact: such as non-uniformity, shading and streaking. Some of them can be corrected, but some are much tougher to remove. In general, the common methods to deal with such problems are (1) water calibration, where each CT machine is carefully calibrated to remove beam-hardening from materials similar to water (2) iterative bone correction: where bones are separated in the first-pass image, then beam-hardening from bones are corrected in the second-pass. However, beam-hardening from materials other than water and bone, such as metal and contrast agent, become very difficult to correct. Even with the correction, conventional CT does not provide quantitative image values, instead, same material at different locations often shows different CT numbers.
The second drawback of the conventional CT is the lack of material characterization. For example, a highly attenuating material with low density can result in the same CT number in the image as a less attenuating material with high density. There is no insight into what the material is made of. Accordingly, the methods and apparatus described herein address the detection and diagnosis of abnormalities related to ischemic heart disease and abnormalities in the structure of the heart""s muscle and valves.
In one aspect, a method for obtaining data is provided. The method includes scanning myocardial tissue of a patient with an Energy Discrimination Computed Tomography (EDCT) system to acquire data, and analyzing the acquired data for at least one of cardiac measurements, diagnosis, and prognosis after interventions.
In another aspect, an Energy Determination Computed Tomography (EDCT) System includes a radiation source, a radiation detector, and a computer coupled to the radiation source and the radiation detector. The computer is configured to acquire data regarding a first energy spectrum of a scan of myocardial tissue of the patient, acquire data regarding a second energy spectrum of the scan, and analyze the acquired data for at least one of cardiac measurements, diagnosis and prognosis after interventions.
In yet another aspect, a computer readable medium encoded with a program is provided. The program is configured to instruct a computer to receive data regarding a first energy spectrum of a scan of myocardial tissue of the patient, receive data regarding a second energy spectrum of the scan, and analyze the acquired data for at least one of cardiac measurements, diagnosis and prognosis after interventions.